Rapid exchange delivery catheter

ABSTRACT

A catheter exchange member is provided for reducing exchange time when replacing one catheter (or similar device) with another in the vascular anatomy of a patient. The catheter exchange member includes a tubular body having a proximal and a distal end and a central lumen. A tapered fixture having a distal port and a proximal opening which is larger than the distal port is attached to the tubular body at the distal port. An elongate shaft is attached to and extends proximally from either the tapered fixture or the tubular body. The exchange member is preferably used within a conventional guiding catheter where the tubular body is advanced through a distal end of the guiding catheter and into the coronary artery while the tapered fixture remains in the guiding catheter. This configuration allows various therapeutic and diagnostic devices to be stored within the guiding catheter just proximal to the tapered fixture. One of the devices can be placed within the coronary artery by simply advancing it through the tapered fixture which channels the device into the tubular body and into the coronary artery. The device may be replaced with another by simply removing it and advancing the second device into the tapered fixture and into the coronary artery

This is a division of application No. 08/271,878 filed Jul. 7, 1994, nowU.S. Pat. No. 5,620,417, the disclosure of which is incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of transluminal catheterprocedures and interventions. In particular, the present inventionprovides a device and method for facilitating the rapid exchange ofvarious therapeutic and diagnostic devices into the coronary arteries.

Percutaneous transluminal treatment of coronary artery diseasefrequently requires performance of multiple diagnostic and/orinterventional procedures, each of which requires introduction of adifferent catheter. For example, intravascular ultrasound is oftenperformed first and requires introducing a catheter having an imagingtransducer into the heart. Following diagnosis, various therapeuticdevices can be introduced into the heart, such as balloon angioplastycatheters, atherectomy catheters, laser ablation catheters, drugdelivery catheters, and the like.

Before most therapeutic and diagnostic devices are introduced into apatient's vascular anatomy, a guiding catheter is first introduced intothe heart as described generally in U.S. Pat. No. 5,163,921, thedisclosure of which is herein incorporated by reference. The guidingcatheter is typically inserted into the femoral artery in the groin andadvanced towards the heart. The guiding catheter is directed through thepatient's aorta until the distal tip of the guiding catheter reaches theostium of one of the coronary arteries. Once the guiding catheter isplaced in the ostium, various therapeutic or diagnostic devices can beinserted through the guiding catheter and into the coronary artery.

In order to introduce these devices beyond the distal end of the guidingcatheter, a guide wire is commonly introduced through the guidingcatheter. The distal end of the guide wire is advanced past the distalend of the guiding catheter and into the coronary artery. With the guidewire in place, a diagnostic or therapeutic catheter can be advanced overthe guide wire and into the area of interest. The diagnostic ortherapeutic catheter includes a lumen for receiving the guide wire, andthe catheter is advanced over the guide wire in a manner often referredto as "tracking".

Frequently, it is necessary to exchange one therapeutic or diagnosticcatheter for another. For instance, after initial diagnosis, it isusually necessary to remove the diagnostic catheter and replace it withan interventional catheter. Moreover, catheters having different sizedballoons are often exchanged in an angioplasty procedure where lesionsof the same vessel often require treatment with different size balloons.Following initial intervention, it is often desirable to reintroduce thediagnostic catheter to assess the progress that has been made. At theend of the treatment, it may be desirable to introduce a drug deliverycatheter to perfuse the lesion with agents to inhibit restenosis. Theexchange of catheters along a guide wire are described in U.S. Pat. Nos.4,748,982; 4,762,129; 4,824,435; 4,850,358; and 5,024,234, thedisclosures of which are hereby herein incorporated by reference.

In a particular procedure for exchanging catheters, the guide wire isleft in place to protect the artery during the exchange. The guide wireis left in the artery because of complications that can arise whenremoving the guide wire, e.g., when the distal tip of the guide wirelifts a lesion flap, when the vessel spasms or abruptly closes makingwire advancement impossible, or when placement of the guide wire simplytakes too much time. To avoid these complications, the wire in thisprocedure is typically maintained in the vessel while the catheterexchange takes place.

Two techniques are generally employed for exchanging catheters when theguide wire is maintained in the artery. The first technique is used withcatheters in which the guide wire lumen extends the full length of thecatheter shaft. These are often referred to as "over-the-wire"catheters. When the "over-the-wire" catheter is withdrawn from thepatient, guide wire position is maintained by holding the guide wire atits proximal end. To maintain a grip on the guide wire until the entirecatheter is withdrawn from the patient, the guide wire must be longenough so that the proximal end of the guide wire can be held in placeuntil the distal end of the catheter exits the patient. After the distalend of the catheter has been withdrawn from the patient, the grip at theproximal end of the guide wire may be withdrawn and the guide wire canbe firmly held distal to the distal end of the catheter. The cathetercan then be completely removed from the patient. The same procedure isperformed in reverse to insert a different catheter into the patient.

In order to simplify catheter exchange, the second technique wasdeveloped which uses a "rapid exchange" catheter design. In the "rapidexchange" catheter, the guide wire lumen does not extend the full lengthof the catheter shaft. Instead, the guide wire exits the catheter shaftat some point near the distal end of the catheter. The remaining lengthof the guide wire runs alongside the catheter shaft until both thecatheter and the guide wire exit the patient. This reduces the necessarylength of the guide wire in comparison to the length required by the"over-the-wire" catheters.

One problem with existing intravascular systems arises from the need toposition therapeutic or diagnostic devices into the narrow arteries ofthe heart The need to place the device over a guide wire requires thatthe distal end of the device be enlarged to accommodate the wire. Theenlarged distal end can prevent the device from entering smallerarteries within the coronary vasculature. To overcome this problem,"common lumen" catheters have been developed as described in U.S. Pat.No. 5,203,338, the disclosure of which is hereby incorporated herein byreference. Common lumen catheters have a distal end having a single orcommon lumen and a proximal portion having at least two lumens, whereone of the proximal lumens serves as a guide wire lumen. The commonlumen catheter is inserted over a guide wire which has previously beeninserted into the patient. After the common lumen catheter has beenpositioned at the desired location in the artery, the guide wire can beretracted from the distal region of the common lumen catheter and intoone of the proximal lumens. This leaves the common lumen positioned inthe distal region and available to receive the therapeutic or diagnosticdevice.

Despite improvements rendered by these techniques, certain difficultiesstill remain in performing coronary artery procedures. For instance,common lumen catheters occupy a substantial volume of the guidingcatheter making it difficult to introduce contrast media through theguiding catheter. Additionally, even though the proximal portion of thecommon lumen is relatively large, space for housing the therapeutic ordiagnostic devices is still limited. Because fewer devices can be storedin the common lumen catheter, the process of catheter exchange isslowed.

For these reasons it would be desirable to provide improved cathetersand methods which overcome or reduce these and other problems.

2. Description of Background Art

Guiding catheters are described in U.S. Pat. Nos. 5,163,921 and4,817,613.

As previously described, "rapid exchange" type catheters are describedin U.S. Pat. Nos. 4,748,982; 4,762,129; 4,824,435; 4,850,358; 5,024,234.

As previously described, "common lumen" catheters are described in U.S.Pat. No. 5,203,338.

Other catheters employing guide wires are described in U.S. Pat. Nos.5,201,316; 5,087,247; and 4,932,413, the disclosures of which are herebyherein incorporated by reference.

SUMMARY OF THE INVENTION

The present invention provides apparatus and methods for facilitatingthe rapid exchange of a variety of devices including therapeuticcatheters, diagnostic catheters, and guide wires into the coronaryarteries of the heart. The apparatus has a very small diameter proximalportion to reduce the occupied volume of the guiding catheter. Moreover,the invention increases the number of devices that can be positionednear the arteries by utilizing the entire interior portion of aconventional guiding catheter to hold the devices. By increasing thenumber of devices that can be held near the desired arteries, the timerequired to exchange these devices can be significantly decreased.

To provide these advantages, a catheter exchange member is positionedwithin a lumen of the guiding catheter near its distal end. The catheterexchange member includes a tubular body with proximal and distal endsand a central lumen. A tapered fixture having a distal port is attachedto the proximal end of the tubular body so that the distal port isaligned with the central lumen. The tapered fixture further includes aproximal opening which is larger than the distal port. An elongate shaftis attached to and extends proximately from either the tapered fixtureor the tubular body. In an exemplary aspect, the tubular body has alength in the range from 5 cm to 35 cm and inner diameter in the rangefrom 0.5 mm to 1.5 mm. In another aspect, the proximal opening of thetapered fixture is radially expandable to a diameter in the range from1.5 mm to 2.5 mm. In a further aspect, the proximal opening has a fixeddiameter in the range from 1.2 mm to 2.0 mm.

In one particular aspect, the elongate shaft is a tubular member havinga central lumen. Attached near the distal end of the tubular body and influid communication with the tubular member is an expandable balloon.Such a configuration allows the catheter exchange member to function asa balloon catheter. By having the catheter exchange member also functionas a balloon catheter, additional space within the guiding catheter canbe provided to store other therapeutic or diagnostic devices.

In another aspect, the tubular member has an infusion port. Through thisport, drugs or other fluids can be delivered to the patient through thetubular member.

In one alternative embodiment of the catheter exchange member, thetapered fixture is a helical coil. In an alternative embodiment, thetapered fixture is a folded cone. In a further alternative embodiment,the tapered fixture includes a plurality of axial spring memberssupporting a flexible membrane.

In an alternative embodiment of the device of the present invention, acatheter exchange member for use in combination with a guiding catheterhaving an access lumen therethrough is provided. The catheter exchangemember includes a tubular body having a proximal and a distal end and acentral lumen. Means are provided at the proximal end of the tubularbody for guiding a distally advancing catheter into the central lumen ofthe tubular body. Means are also provided for positioning the tubularbody within the guiding catheter.

In a preferred aspect, the guiding means includes a tapered fixturehaving a distal end attached to the tubular body, a proximal openinghaving a diameter in the range from 1.2 mm to 2.0 mm, and a guidebarrier between the distal end and proximal opening. Exemplaryembodiments of the tapered fixture include a helical coil, a foldedcone, or a plurality of axial spring member supporting a flexiblemembrane. In a further aspect, the positioning means includes anelongate shaft attached to and extending proximally from the guidingmeans.

In another aspect, the elongate shaft is a tubular member having acentral lumen. Attached near the distal end of the tubular body and influid communication with the tubular member is an expandable balloon.Such a configuration allows the catheter exchange member to function asa balloon catheter. In a further aspect, the tubular member has aninfusion port. Through this port, drugs or other fluids can be deliveredto the patient through the tubular member.

The invention further provides a method for introducing an interactiveelement at the distal end of a catheter into a coronary artery.According to the method, a guiding catheter is introduced into thevasculature of a patient so that a distal end of the guiding catheter isat a coronary ostium. A tubular body is positioned within a lumen of theguiding catheter so that a proximal end of the tubular body is disposedwithin the guiding catheter and a distal end of the tubular body liesnear a target location in the coronary artery. The distal end of theinteractive catheter is then advanced through the lumen of the guidingcatheter and into an open proximal end of the tubular body. Theinteractive catheter is then advanced through the lumen of the tubularbody to the target location in the coronary artery.

In one particular aspect, the tubular body is positioned by axiallytranslating an elongate shaft attached to the tubular body through thelumen of the guiding catheter.

In another aspect of the method, the proximal end of the tubular bodyincludes a tapered fixture which acts as a guide to facilitate entry ofthe distal end of the interactive catheter into the lumen of the guidingcatheter as the interactive catheter is advanced. In a further aspect,the tapered fixture includes a radially expandable proximal end forreceiving the distal end of the interactive catheter. In yet anotheraspect, the interactive catheter is advanced into the tubular bodywithout a movable guide wire.

In an exemplary aspect of the method, a guide wire is introduced throughthe guiding catheter into the coronary artery, and the tubular body ispositioned over the guide wire. After the tubular body is at the desiredlocation, the guide wire is withdrawn from the tubular body prior toadvancing the distal end of the interactive catheter.

In yet another aspect, the distal end of the interactive catheter iswithdrawn-from the tubular body. The distal end of a second catheterhaving an interactive device at its distal end is then advanced into theopen proximal end of the tubular body to the target location in thecoronary body.

In still another aspect, the tubular body is retracted relative to theguiding catheter to expose the interactive device within the targetregion of the coronary region. The tubular body can be retracted bywithdrawing an elongate shaft attached to the tubular body through thelumen of the guiding catheter. In a preferred aspect, the interactiveelement is selected from the group consisting of ultrasonic transducers,angioplasty balloons, cutting blades, abrasive elements, fiber opticelements, and perfusion catheters.

In one particular aspect, a balloon near the distal end of the tubularbody is expanded. Preferably, the balloon will be expanded in an areahaving a lesion. In a further aspect, a fluid is delivered through atubular member that is attached to the tubular body. Preferably, thefluid will be a drug.

In yet another aspect of the method, the interactive catheter is aballoon catheter having a stent positioned around a balloon at a distalend of the balloon catheter. The balloon catheter is advanced throughthe tubular body until the stent is positioned at the target location.Once the stent is at the target location, the catheter exchange memberis retracted until the stent is beyond the distal end of the tubularbody. The balloon is then expanded to position the stent in the artery.The catheter exchange member can then be advanced until the tubular bodyis within the expanded stent.

In a further method a stent attached to a distal end of an interactivecatheter is introduced into a coronary artery. According to the method,a guiding catheter is introduced into the vasculature of a patient sothat a distal end of the guiding catheter is at a coronary ostium. Thestent is then positioned snugly within a tubular body near a distal endof the tubular body. The tubular body having the stent is then insertedwithin a lumen of the guiding catheter so that a proximal end of thetubular body is disposed within the guiding catheter and the distal endof the tubular body lies near a target location in the coronary artery.The distal end of the interactive catheter having the stent is thenadvanced beyond the distal end of the tubular body to place the stent atthe target location in the coronary artery.

In one particular aspect of the method, the interactive catheter is aballoon catheter having a balloon at its distal end. The stent iscrimped to the balloon before placement of the balloon catheter into thetubular body so that both the stent and the tubular body can be advancedtogether through the guiding catheter. Once the stent is beyond thedistal end of the guiding catheter; the balloon is expanded to positionthe stent within the target location.

In another aspect, the stent is self-expanding so that the stent canself-expand into the target area upon exiting the tubular body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a catheter exchange member having a folded cone for atapered fixture according to the present invention.

FIG. 1A illustrates an alternative embodiment of the catheter exchangemember of FIG. 1 having a tubular member as a positioning shaft.

FIG. 2 illustrates a catheter exchange member having a helical coil fora tapered fixture according to the present invention.

FIG. 3 illustrates a catheter exchange member having a plurality ofaxial spring members supporting a flexible membrane for a taperedfixture according to the present invention.

FIG. 4 illustrates a catheter exchange member disposed within a lumen ofa guiding and having therapeutic and diagnostic devices located thereinaccording to the present invention.

FIG. 5 is a cross-section view showing a catheter exchange memberdisposed with a guiding catheter and having therapeutic and diagnosticdevices located therein according to the present invention.

FIG. 6 is a view of the guiding catheter of FIG. 5 taken along line6--6.

FIGS. 7-9 illustrate an exemplary method for inserting a guidingcatheter into a coronary ostium and using a catheter exchange member tofacilitate the placement of therapeutic and diagnostic devices into thecoronary arteries.

FIG. 9A illustrates an alternative use of the catheter exchange memberof FIGS. 7-9 when provided with an expandable balloon.

FIGS. 10-12 illustrate a method for utilizing a catheter exchange memberto both facilitate the placement of a stent within the coronary arteriesand to facilitate the exchange of therapeutic and diagnostic deviceswithin the expanded stent according to the present invention.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The present invention provides a device and method for introducing andfacilitating the rapid exchange of therapeutic, diagnostic, and otherapparatus into the coronary arteries. The device comprises a catheterexchange member which is used within an access lumen of another cathetera guiding catheter introduced to the coronary arteries. The catheterexchange member includes a tubular body having a proximal and a distalend and a central lumen. Attached at the proximal end of the tubularbody is a tapered fixture having a distal port and a proximal openingwhich is larger than the distal port. The distal port of the taperedfixture is aligned with the central lumen, and an elongate shaft isattached to and extends proximally from either the tapered fixture orthe tubular body.

As described hereinafter, the tubular body serves as a path for avariety of therapeutic or diagnostic devices to a target location in thecoronary artery. The therapeutic or diagnostic devices are advancedthrough a distal end of the tubular body and into the target location inthe artery. In a preferred aspect, the tubular body has a length in therange from 5 cm to 35 cm and an inner diameter in the range from 1.2 mmto 2.0 mm. Exemplary materials for constructing the tubular body includepolyethylene, polyurethane, silicone, and the like.

The tapered fixture serves as an anchor to maintain the catheterexchange member at a desired location in the guiding catheter and as aguide for delivering catheters from the guiding catheter into thetubular body. Preferably, the tapered fixture anchors the catheterexchange member near the distal end of the guiding catheter allowing thetubular body to pass through the distal end of the guiding catheter andinto the coronary artery. The tapered fixture can be constructed in avariety of ways, an important feature being that it is able to maintainthe catheter exchange member at the desired location in the guidingcatheter. As described in detail hereinafter, the tapered fixture can bea helical coil, a folded cone, a plurality of axial spring membersupporting a flexible membrane, or the like. These embodiments providethe necessary anchoring to hold the catheter exchange member in place.Preferably, the proximal opening of the tapered fixture will be radiallyexpandable to a diameter in the range from 1.5 mm to 2.5 mm. This allowsthe tapered fixture to be adjustable fit within guiding catheters havingdiffering or variable inner diameters. Alternatively, the proximalopening of the tapered fixture can have a fixed diameter in the rangefrom 1.2 mm to 2.0 mm.

The tapered fixture is preferably configured so that contrast media,such as an angiographic die, can pass through the catheter exchangemember and into the coronary arteries. The contrast media is used toenhance fluoroscopic imaging of the proper target location in theartery. To allow passage of the contrast media, the tapered fixture willpreferably have a perforate structure, for example being provided withholes, slits, openings, or the like.

The tapered fixture also serves to direct catheters, guide wires, orsimilar devices into the tubular body when distally advanced through theguiding catheter towards the coronary artery. When a distal tip of oneof these devices is advanced through the guiding catheter, it willengage the walls of the tapered fixture and be directed into the tubularbody. Hence, a variety of these devices can be held within the guidingcatheter just proximal to the catheter exchange member, the limitingfactor being the inner diameter of the guiding catheter and the size ofthe devices. When one of the devices is needed at the target location inthe artery, it is simply advanced from the guiding catheter into thetubular body and into the coronary artery. If the device is to beexchanged for another, it is simply retracted until its distal end iswithdrawn from the catheter exchange member back into the guidingcatheter. Another device can then advanced through the tapered fixtureand into the tubular body.

By having the tapered fixture anchor the catheter exchange member to theguiding catheter and by having the tapered fixture direct interactivedevices into the coronary artery, the guiding catheter itself can beused to store a variety of catheters having an assortment of interactivedevices. The assortment of interactive elements can be those that areselected from the group consisting of ultrasonic transducers,angioplasty balloons, cutting blades, abrasive elements, and fiber opticelements. These interactive elements can be used for either therapeuticor diagnostic procedures. By utilizing the entire space of the accesslumen of the guiding catheter (less the small area required by theelongate shaft), the number of these devices that can be stored isincreased. Further, by storing these devices within the guiding catheteritself, the devices can more rapidly be exchanged with each other when adifferent device is required within the coronary artery.

The elongate shaft is used to advance the catheter exchange member intoand along the guiding catheter. Hence, the elongate shaft should havesufficient rigidity and column strength to be able to advance thecatheter exchange member through the guiding catheter lumen. In anexemplary embodiment, the elongate shaft is a flexible rod or"hypotube". The rod or "hypotube" is typically constructed fromstainless steel or other medically acceptable metals. Alternatively, theelongate shaft can be a tubular member with a central lumen fordelivering fluid to a location near the distal end of the tubular body.The fluid delivered can be used to inflate a balloon near the distal endof the tubular body, or can be a drug that is delivered to the patientthrough a port in the tubular member.

Referring to FIG. 1, an exemplary embodiment of a catheter exchangemember 10 having a cone shaped tapered fixture 12 is shown. Attached toa distal port 14 of the tapered fixture 12 is a tubular body 16. Thetapered fixture 12 further includes a proximal opening 18 which islarger in diameter than the distal port 14.

The tapered fixture 12 has a slot along its length resulting in twooverlapping ends which form a folded cone. This configuration allows theproximal opening 18 to be radially expandable to a diameter necessary toengage the walls of the guiding catheter and to provide an anchor.Alternatively, the proximal opening 18 can be configured so that itsdiameter is fixed, i.e. by not slitting the tapered fixture. By fixingthe diameter, the catheter exchange member 10 can be advanced through aguiding catheter having a decreasing inner diameter at its distal end sothat its proximal opening 18 engages the guiding catheter near itsdistal end.

The tapered fixture 12 is preferably constructed of the same materialused to construct the tubular body. Alternatively, the tapered fixture12 can be constructed of polyethylene, polyurethane, silicone, and thelike. The use of these materials allow for advantages such as strength,biocompatibility, low friction, low cost, and ease of manufacture.

Attached anywhere along the tapered fixture 12 or the tubular body 16 isa flexible rod 24. As previously described, the rod is used to advancethe exchange member 10 through a guiding catheter towards the coronaryartery.

The tubular body 16 is flexible so that it can be advanced into thedistal regions of the coronary arteries while also having sufficientstrength to advance the catheter exchange member along the guidingcatheter. Optionally, the tubular body can have a distal tip 26 throughwhich a guide wire or interactive device can be advanced into thecoronary artery. Optionally the flexible rod 24 could also be attachedto the distal tip 26.

In an exemplary use, the catheter exchange member 10 is inserted into aguiding catheter beginning with the distal tip 26. The flexible rod 24is then used to advance the exchange member 10 through the guidingcatheter toward the coronary artery. The distal tip 26 and a distalportion of the tubular body 16 are advanced through a distal end of theguiding catheter and into the desired regions of the coronary artery.The tapered fixture 12 engages the walls of the guiding catheter andanchors the exchange member 10 within a distal portion of the guidingcatheter. Since the tapered fixture 12 is radially expandable, theexchange member 10 can be configured to engage the guiding catheter atany desired location. Once properly anchored, therapeutic or diagnosticdevices can be advanced into the guiding catheter and up to the proximalopening 18. When one of these devices is selected to be advanced intothe desired location in the coronary artery, the device can simply beadvanced into the tapered fixture 12 which will direct the device intothe tubular body 16, out the distal tip 26, and into the desiredlocation.

The catheter exchange member 10 can be provided with a tubular member124 in place of the flexible rod 24 as shown in FIG. 1A. Tubular member124 can be attached anywhere along the tapered fixture 12 or the tubularbody 16. Tubular member 124 includes a central lumen 126 for deliveringa fluid. The fluid can be used to inflate an expandable balloon 128 nearthe distal end of the tubular body 16. Preferably, the balloon 128 willbe an angioplasty balloon. In this manner, the tubular body 16 and theballoon 128 can function as an angioplasty balloon catheter in additionto functioning as an exchange member. Such a configuration eliminatesthe need to store this type of balloon catheter in the guiding catheter,thereby providing additional space in the guiding catheter which can beused to store other therapeutic or diagnostic devices.

The tubular member 124 can also be provided with a plurality of infusionports 130. By providing ports 130, the tubular member 124 can be used asan infusion tube for administering drugs or other fluids to the patient.

Tubular member 124 is preferably constructed of a stiff plastic or metaltube so that the tubular member has sufficient stiffness to push anddirect the catheter exchange member 10 into the coronary artery.Although shown with the embodiment of FIG. 1, the tubular member 124 canequally be included in the embodiments shown in FIGS. 2 and 3 which aredescribed hereinafter.

An alternative embodiment of a catheter exchange member is shown in FIG.2 and is designated by reference numeral 28. The catheter exchangemember 28 is essentially identical to the catheter exchange member 10 ofFIG. 1 except for the tapered fixture. For convenience of discussion,all of the elements of the catheter exchange member 28 will useidentical reference numerals as illustrated in FIG. 1 except for thetapered fixture. The catheter exchange member 28 of FIG. 2 includes ahelical coil tapered fixture 30 and is constructed from a tapered springcoil. A distal end of the coil is attached to a proximal end of thetubular body 16. The proximal opening 18 of the tapered fixture 30contacts the lumen walls of the guiding catheter and serves to funneldevices that are advanced through the guiding catheter and into thetubular body 16.

One advantage of using a tapered spring coil is that it allows contrastmedia to be delivered into the artery for angiographic assessment. Thelayers of the coils are spaced sufficiently apart for delivery of thecontrast media, and are also sufficiently close together to preventguide wires from slipping through the tapered fixture 30 when distallyadvanced. The gap between the layers of the coil will preferably be inthe range from 0.10 mm to 0.25 mm, and more preferably at about 0.20 mm.A preferable material for the helical coil is stainless steel, nitinol,nylon, and the like. The flexible rod 24 can be attached anywhere alongthe tapered fixture 30 or alternatively anywhere along the tubular body16. Preferably, the rod 24 will be attached to the proximal coil layers.

Yet another embodiment of a catheter exchange member 32 is shown in FIG.3. The catheter exchange member 32 contains elements essentiallyidentical to the catheter exchange member of FIG. 1 except for thetapered fixture. The catheter exchange member 32 employs a "umbrellatype" tapered fixture 34. The tapered fixture 34 has a plurality ofaxial spring members 36 that support a flexible membrane 38. The axialspring members 36 are outwardly biased in a radial direction causing theproximal opening 18 to be larger than the distal port 14. The taperedfixture 34 functions similar to a conventional spring loaded umbrella.The spring members 36 serve to engage the inner walls of the guidingcatheter to provide an anchor. The spring members along with theflexible membrane 38 also serve to channel or funnel any devicesinserted through the guiding catheter and into the tubular body 16. Theflexible membrane 38 is preferably constructed of polyethylene,polyurethane, silicone, and the like and allows fluids, such as contrastmedia, to flow to the coronary arteries. The tapered fixture 34 can beused with different sizes of guiding catheters because of the radiallyexpandable axial spring members 36 which engage the inner walls of theguiding catheter.

Referring to FIG. 4, an exemplary embodiment of catheter exchange member40 in combination with a guiding catheter 42 will be described. Theguiding catheter 42 is initially placed in the coronary ostium and aguide wire 44 is advanced through the guiding catheter 42 and into adistal portion of the coronary artery. The catheter exchange member 40is then advanced over a proximal end of the guide wire 44 and into theguiding catheter 42. The exchange member 40 can be advanced over theentire length of the guide wire 44. Alternatively, the guide wire 44 canbe advanced only through a distal portion of the tubular body 48 so thatonly a certain percentage of the tubular body 48 will track over theguide wire 44 and into the coronary artery.

To advance the exchange member 40 through the guiding catheter 42 andinto the coronary artery, a flexible rod 50 attached to a taperedfixture 52 (or to the tubular body 48) of the catheter exchange member40 is axially advanced to direct the exchange member 40 along the guidewire 44. The exchange member 40 is advanced through the guiding catheter42 until it reaches a distal portion of the guiding catheter 42. Thetubular body 48 is then advanced through a proximal end of the guidingcatheter 42 and into a distal portion of the coronary artery while thetapered fixture 52 remains anchored in the guiding catheter 42.

Once the tubular body 48 is at the desired location, the guide wire 44can be withdrawn into the guiding catheter 42. Diagnostic andtherapeutic devices, such as an ultrasound imaging core 54 or a ballooncatheter 56 can be advanced into the guiding catheter 42 and up to thecatheter exchange member 40. Alternatively, the guide wire 44 can beleft in the artery and the balloon catheter 56 advanced over the guidewire 42 as shown in FIG. 4.

The number of devices that can be stored in the guiding catheter 42depends both upon the size of the guiding catheter 42 and the size ofthe devices. To insert one of these devices into the coronary artery, itis simply advanced through a proximal opening in the tapered fixture 52which directs the device into the tubular body 48 where it can befurther advanced into the artery. If another device is needed within theartery, the first device can be removed by pulling it from the tubularbody 48 and advancing the second device into the tapered fixture 52where the second device will be directed into the tubular body 48 andinto the coronary artery.

As previously described, when positioning a device such as a ballooncatheter 56 within the tubular body 48, it is often necessary to injectcontrast media through the tapered fixture 52 so that the location ofthe balloon can fluoroscopically be determined. The guiding catheter 42includes a port 58 for injecting the contrast media into the guidingcatheter. The tapered fixture 52 is configured so that the contrastmedia can pass therethrough and allow for fluoroscopic positioning ofthe balloon catheter 56.

Referring to FIGS. 5 and 6, an enlarged view of a catheter exchangemember 60 is shown to illustrate the positioning of various diagnosticor therapeutic devices when stored within a guiding catheter 62. Theguiding catheter 62 will have a central lumen with an inner diameter inthe range from about 1.5 mm to 2.5 mm. The catheter exchange member willbe small enough to enable it to be advanced through the central lumen.When the catheter exchange member 60 is placed within the guidingcatheter 62, the entire area of the central lumen proximal to thecatheter exchange member 60 can be used to store various therapeutic anddiagnostic devices such as an ultrasound imaging transducer 64 and aballoon catheter 66.

The balloon catheter 66 will typically have a diameter in the range from0.5 mm to 1.0 mm, and the imaging transducer 64 will typically have adiameter in the range from 0.3 mm to 1.0 mm. Also stored within thelumen of the guiding catheter 62 is a flexible rod 68 that is used toadvance the exchange member 60 as previously described. This willtypically have a diameter in the range from about 0.1 mm to 0.25 mm. Thecentral lumen of the guiding catheter 62 is large enough to accommodatea plurality of devices having diameters in the ranges as just described,thereby allowing for a number of devices to be rapidly exchanged andpositioned into the coronary artery.

An exemplary method of using a catheter exchange member to facilitatethe exchange of therapeutic and diagnostic devices in the coronaryarteries is shown in FIGS. 7-9. A guiding catheter 80 is initiallydirected through the aorta 82 until a distal tip 84 reaches the coronaryostium 86 of the main coronary artery 88. The coronary artery 88delivers oxygenated blood to the myocardium 90. Along a branch of thecoronary artery 88 is a lesion 92 which restricts blood flow. Theguiding catheter 80 serves as a guide for therapeutic or diagnosticdevices that are directed to the lesion 92.

As shown in FIG. 8, a catheter exchange member 94 is inserted through aproximal end of the guiding catheter 80 until a tapered member 96 of thecatheter exchange member 94 is near the distal tip 84. At this point, atubular body 98 of the catheter exchange member 94 will extend into thecoronary artery 88 and near the lesion 92. A rod 100 is used to advancethe catheter exchange member 94 through the guiding catheter 80. Avariety of therapeutic or diagnostic devices, such as a balloon catheter102 and a ultrasonic imaging transducer 104, can then be advanced intothe guiding catheter 80 until just proximal to the catheter exchangemember 94.

One of these devices can then be selected and advanced through thecatheter exchange member 94 and into the coronary artery 88. As shown inFIG. 9, the balloon catheter 102 is advanced into the catheter exchangemember 94 and is funneled into the tubular body 98 by the tapered member96. A distal tip 106 of the balloon catheter 102 is advanced beyond thetubular body 98 until it reaches the lesion 92. The balloon catheter 102is then ready to assist in the desired therapy. After therapy, theballoon catheter 102 can be withdrawn from the catheter exchange member94 and another device inserted in its place.

The catheter exchange member 94 can be used to facilitate a variety ofother procedures within the coronary artery. For example, before therapyis performed, a diagnostic procedure may be required. In that event, theultrasound imaging transducer 104 may first be placed near the lesion 92by advancing it from the stored position just proximal to the catheterexchange member 94. After imaging the artery, the imaging transducer 104is withdrawn from the tubular body 98 and stored in the guiding catheter80 just proximal to the catheter exchange member 94.

As another example; the tubular body 98 can be advanced into the lesion92 before a therapeutic or diagnostic device is advanced into thecatheter exchange member 94. The therapeutic or diagnostic device, suchas the balloon catheter 102, can be advanced into the tubular body 98until reaching the lesion 92. The catheter exchange member 94 can thenbe withdrawn from the lesion 92 to expose the balloon to the artery.Balloon dilation may then occur. After treatment is completed, theexchange member 94 can be readvanced over the balloon catheter 102 untilthe distal end of the tubular body 98 is once again established in thedesired location.

In a further example, a guide wire can be stored in the guiding catheter80 and can be advanced from its stored position into the coronary arteryat any time.

In an alternative method, the catheter exchange member 94 can beprovided with a tubular member 200 as shown in FIG. 9A. Tubular member200 has a central lumen in fluid communication with a balloon 202 nearthe distal end of the tubular body 98. The inclusion of the balloon 202allows the catheter exchange member 94 to function as a balloon catheterin addition to functioning as an exchange member. For instance, insteadof advancing the balloon catheter 102 of FIG. 9 to the lesion 92, thetubular body 98 can be advanced until the balloon 202 is near the lesion92. At this point, the balloon dilation can occur as shown in FIG. 9A.By having the catheter exchange member 94 also function as a ballooncatheter, another therapeutic or diagnostic device (such as a cuttingblade 204) can be substituted for the balloon catheter 102 of FIG. 9.The therapeutic or diagnostic devices stored in the guiding catheter canbe advanced into the tubular body 98 as previously described.

Optionally, the tubular member 200 can be used to deliver drugs or otherfluids to the patient by providing a plurality of infusion ports 206. Ofcourse, the infusion ports 206 would be closed if balloon dilation wereproscribed so that the balloon inflation fluid would reach the balloon202. Once the catheter exchange member 94 is in the desired position,drug therapy can occur by injecting drugs through the tubular member 200which will exit to the patient from the infusion ports 206. Preferably,the balloon 202 will not be included if infusion ports 206 are employedfrom drug delivery.

In a further use, the catheter exchange member can be used to assist inplacing a conventional stent within the coronary artery. Conventionalstents, such as those commercially available from Johnson & Johnson andCook, are applied to an area of the artery having a lesion by a ballooncatheter. The stent is typically crimped over a deflated balloon on thecatheter. The balloon is used to expand the stent in the artery wheninflated Alternatively, the stent can be self-expanding and need not becrimped over a balloon. Such stents will preferably be constructed ofnitinol having shape memory.

Typically, a sheath is placed over the stent during insertion. Thesheath is then retracted to expose the stent to the artery and the stentis deployed. The catheter exchange member of the present invention canbe used as a sheath to protect the stent during insertion into thelesionous area. After the stent has been appropriately applied, thecatheter exchange member can then be used as previously described todirect any one of a variety of therapeutic or diagnostic devices into anarea within the expanded stent.

An exemplary use of a catheter exchange member to insert a stent isshown in FIGS. 10-12. Initially a guiding catheter 110 is inserted intothe patient until a distal tip 112 reaches the coronary ostium 114 aspreviously described. A catheter exchange member 116 is then advanced bya shaft 117 along the guiding catheter 110 until a distal end 118 of thecatheter exchange member 116 reaches a lesion 120 as shown in FIG. 10. Aballoon catheter 122 having a stent 124 over a balloon and an ultrasonicimaging transducer 126 are then inserted into the guiding catheter 110and advanced until just proximal to the catheter exchange member 116.The balloon catheter 122 is then advanced into the catheter exchangemember 116 until the stent 124 reaches the lesion 120.

The catheter exchange member 116 is then withdrawn from the regionhaving the lesion 120, and the balloon on the catheter 122 is inflatedto expand the stent 124 as shown in FIG. 11. Once the stent 124 isexpanded, the catheter exchange member 116 is again advanced so that thedistal end 118 is within the expanded stent 124 as shown in FIG. 12. Theultrasound imaging transducer 126 is then inserted into the distal end118 of the catheter exchange member 116 where the imaging transducer 126can be used to help determine the location of the stent 124.

In an alternative method, the stent 124 can be placed within thecatheter exchange member 116 near the distal end 118 before the catheterexchange member 116 is introduced into the guiding catheter 110.Preferably, the stent 124 will be snugly fit within the catheterexchange member 116. Both the catheter exchange member 116 and theballoon catheter 122 having the stent 124 are then advanced togetherthrough the guiding catheter. In this manner, the catheter exchangemember 116 serves as a sheath to prevent inadvertent embolization of thestent 124 before reaching the target location. Once the catheterexchange member is inserted, the stent can be positioned at the targetlocation as previously described.

Although the foregoing invention has been described in some detail byway of illustration and example, for purposes of clarity ofunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the appended claims.

What is claimed is:
 1. A catheter exchange member comprising:a tubularbody having a proximal end, a distal end, and a central lumen; a taperedfixture having a distal port connected to the tubular body and alignedwith the central lumen and a proximal opening which is larger than thedistal port, the tubular body and the tapered fixture forming asubassembly, and an elongate shaft having a proximal end and a distalend, wherein the distal end is fixedly attached to the subassembly andwherein the proximal end is disposed proximally from the subassembly. 2.A catheter exchange member as in claim 1, wherein the tubular body has alength in the range from 5 cm to 35 cm and an inner diameter in therange from 0.5 mm to 1.5 mm.
 3. A catheter exchange member as in claim 1wherein the proximal opening has a fixed diameter in the range from 1.2mm to 2.0 mm.
 4. A catheter exchange member as in claim 1, wherein theelongate shaft is a flexible rod.
 5. A catheter exchange member for usein combination with a guiding catheter having an access lumentherethrough, said catheter exchange member comprising:a tubular bodyhaving a proximal end, a distal end, and a central lumen; means at theproximal end of the tubular body for guiding a distally advancingcatheter into the central lumen of the tubular body, the guiding meanscomprising a tapered fixture having a distal end attached to the tubularbody, a proximal opening having a diameter in the range from 1.2 mm to2.5 mm; and an elongate shaft having a proximal end and a distal end,wherein the distal end is fixedly attached to the tubular body or theguiding means, and wherein the proximal end of the shaft is disposedproximally of the guiding means to position the tubular body within theguiding catheter.
 6. A catheter exchange member as in claim 5, whereinthe tubular body has a length in the range from 5 cm to 35 cm and aninner diameter in the range from 0.5 mm to 1.5 mm.
 7. A catheterexchange member as in claim 5, wherein the guiding means furthercomprises a guide barrier between the distal end and proximal opening.8. A catheter exchange member as in claim 7, wherein the proximalopening has a fixed diameter in the range from 1.2 mm to 2.0 mm.
 9. Acatheter exchange member as in claim 5, wherein the guiding means andthe tubular body form a subassembly, and wherein the elongate shaft isattached to and extends proximally from the subassembly.
 10. A catheterexchange member as in claim 9, wherein the elongate shaft is a flexiblerod.